Thinking about how I use email
I've recently wound up thinking that sysadmins probably use email a little bit differently than other people, so I've decided to write down some words on how I use email (as distinct from the tools I use for this).
A bunch of my email is archives, in a sprawling set of folders. I archive things for a variety of reasons; the major ones are more or less sentimentality (email to and from some people), for active future reference (for example, I keep a copy of the current build instructions for all of our machines), and as a genuine archive (for example, I keep a copy of all conversations with vendors). The important thing about archives is that I almost never look at them; they are not active email. As a result they're not really interesting in terms of email handling.
My active email is in my inbox and spinoffs from it. My habit is to almost always keep entire conversations, start to finish, until the whole issue has been concluded (at which point I'll delete the entire thread). Conversations that I'm involved in or might be almost always stay in my inbox; conversations that I'm just monitoring I try to shove off to a side folder (although I don't usually manage to do it right away; often I hope that the conversation is only going to be a short one, so I can delete it soon). In short and in theory, my inbox is for active things that concern me, things that I need to stay on top of (including things where I need to do something and then send a reply).
(The problem with the side folders is that I never look at them, so they usually have plenty of now-concluded conversations that I could delete. But pruning them is the kind of low priority boring work that's hard to get around to.)
In general, what stays in my inbox is messages and conversations where I want to do something as a reaction to them; reply to them, read something they're pointing me to, keep track of whether a condition has cleared, and so on. While I get a constant flow of automated status messages, alerts, and so on, I read (or skim) these and immediately delete them unless they're actually something I need to react to. I try not to use my inbox as a todo list (I have a separate system for that), but I'm not always entirely successful.
(One reason not to use my inbox as a todo list is that my mail client only shows me a few of the most recent messages. Once a message disappears off that list I'm no longer being reminded of it and poof, it's gone from my mind.)
I don't have a good solution for things that I want to get around to but that I'm not. I don't always want to delete them and they shouldn't really stay in my inbox for long, but I'm always reluctant to refile them somewhere else because I know that makes it basically sure I'll never deal with them (and it's hard to give up on the idea that someday I will etc).
I should mention this explicitly: I don't tolerate unread messages in my inbox. I always read (or skim) everything right away, whether or not I do anything with it. To make this viable, I strongly limit what I let get into my inbox; almost everything that winds up there is at least theoretically important and relevant to me.
(I almost never subscribe to mailing lists (there are better
alternatives) and I've ruthlessly pruned various
web site notifications and so on down to things that I actually care
about. Every so often I conduct another slash and burn round; for
extreme cases I 'unsubscribe' by deleting the email alias that I gave
wherever it was. As for automated status messages from local stuff, I
procmail away as many of the 'everything is fine' status messages as I
can and I try to make systems quiet in general.)